1. Field on the Invention
The present invention pertains to flexible foam compositions and in particular to flexible polyurethane flame-retarded foam compositions and methods for the preparation thereof. More particularly, the present invention relates to the preparation of flexible polyurethane flame-retarded foam compositions which will retain their resistance to cigarette smoldering even after service.
2. Description of the Prior Art
The preparation of flexible polyurethane flame-retardant foam compositions are generally well known as evidenced by the following prior art. U.S. Pat. No. 4,022,718 teaches the preparation of high resilience cold-cured polyurethane foams incorporating 2,3-dibromo-1,4-butenediol as a chain extender and flame-retardant component. U.S. Pat. No. 4,147,847 teaches a method of preparing flexible, flame-retarded, polyurethane foams by employing specific foam stabilizers which reduce the required amount of normal flame-retardant additives. U.S. Pat. No. 4,162,353 teaches the preparation of flexible polyurethane foams incorporating therein a halo-substituted alkyl phosphate such as, for example, tris(2-chlorethyl)-phosphate and an unsubstituted trialkylphosphate such as, for example, triethylphosphate. U.S. Pat. No. 4,221,875 teaches the preparation of rigid polyurethane foam incorporating melamine as the sole flame retardant component. U.S. Pat. No. 4,293,657 teaches the use of melamine dispersions in polyol wherein the melamine has a particle size of less than 10 .mu.m and is produced by crushing in situ in the polyol at high localized energy densities. A dispersion stabilizer is also a necessary ingredient of the dispersion. U.S. Pat. No. 4,385,131 teaches the preparation of rebonded polyurethane foam incorporating urea and/or melamine for resistance to smoldering combustion. None of the prior art teaches, however, that incorporating an amount of melamine from about 5 weight percent to about 25 weight percent of the weight of the flexible foam, having a density from about 1.2 lbs/ft.sup.3 to about 4 lbs/ft.sup.3 will result in a foam resistant to cigarette smoldering upon being subjected to flex fatigue similar to actual survive.